Fifty extras including 38 wides did not help as Tech were dismissed for 251 after 41 overs, which was a solid recovery from 97-5.
Michael Engelbrecht, about to have an important day, gave away his fair share in five overs, but still got both the young Canadians in Akhil Kumar (21) and Akash Gill (20) when they were going better than a run a ball.
Tyler Lock, Kashish Nauhria and Ross Kinnerley all departed cheaply, before Jess Watkin (35) and Quinn Mailman (46) led the comeback with 73 runs in less than ten overs.
Hunter Morrison (24), Fraser Kinnerley (16) and Dominic Lock (13) carried it on until the Marist bowlers would eventually get their line right and catch them out swinging, with Sam O'Leary (3-30) getting those three Tech batsmen out in his six overs, while Zak O'Keeffe (2-57) was the only one to bowl his full 10 overs.
In reply, Marist seemed like they were going to wrap up the game in less than 25 overs on the baked pitch as M OLeary (54) and Stewart had the 100 run partnership raised in less than ten overs, taking it to Gill and Kinnerley with boundaries around the park.
O'Keeffe (31) kept up the onslaught and when he went at 153-2 in the 19th over, Marist were cantering.
However, Watkin (3-47) again proved that Whanganui batsmen are not getting enough time in front of spinners, of which there are only a few, as she took a double wicket maiden to get Zander Engelbrecht and John McIlraith after previously dismissing O'Keeffe.
Tech could now bring back Kinnerley (2-53) and it appeared the tide had turned when Mark Fraser fell to him first ball.
Stewart suddenly had to slow right up and be watchful with wickets tumbling at the other end, as Craig Thorpe was trapped in front, before Sam O'Leary (18) tried to up the ante but ultimately holed out off Morrison.
Raponi Tofa had his middle stump tore out of the ground by Gill, and it was all on Stewart's shoulders with 18 overs left but only two wickets at 215-8.
With Watkin bowled out and Kinnerley nearly done, Tech brought on Chris Friedel but Stewart quickly attacked him with a six and a four, while at the other end, Michael Engelbrecht (6 not out) was surviving – even if he often played and missed as well as dropping his bat on one last-ball single and having to slide to the crease baseball style.
Kumar joined Gill in trying to break the partnership, but the pair kept up the singles.
Kinnerley returned, but the Marist camp was soon whooping as Stewart struck the last ball of his ninth over to the boundary, and then Engelbrecht immediately hit Gill back over his head to tie the scores, before popping the next ball through the cordon for the matchwinner.
There was no raucous cheering over on the No1 pitch as United just got into their business against a Marton team missing enough frontliners to count on two hands.
With Matthew Boswell picking up a confidence-boosting 94 from 102 balls, just in time for the next Furlong Cup match, United went a run-a-ball and only really got out playing shots, amassing 322-8.
Greg Smith (37) and Gerard Hobbs (46) worked with Boswell to get United over 200 before the 30th over, then Simon Badger (63) and Martin Pennefather (31 not out) carried it on, although they both lost other batting partners as all seven Marton bowlers got wickets, the best being Freddy Lane (2-35).
The rot continued as only veteran Dominic Rayner (16) got close to double figures in amongst the first eight Marton batsmen, as Ritesh Verma (5-25) and Badger (3-19) cleaned them up.
Wanting it done, United went with no less than six slips, which led to a bit of a flurry from Andre Canderle (29 not out), who was able to take four boundaries off one Verma over when he drove to a empty outfield.
However, James Pennefather (2-14) came on and swiftly removed Canderle's remaining young partners to have Marton out of there in 26 overs for less than 100.
At the school grounds in hot conditions, Collegiate lacked urgency and imagination in the field against Levin Old Boys, and the bowlers sending down 36 wides only added to the monotony.
Levin's Dion Sanson (74) carried his bat through from the 12th to the 48th over, following on from Bailey Te Tomo (39) and then supported by Nick O'Brien (27) and Daniel Parker (17 not out).
Although the Collegiate pace bowlers could be accurate when their heads were in the right space, specifically Hadleigh O'Leary (3-47), Charlie Greatbatch (2-27) and Ben Kelt (2-52), coach Warren Marr was becoming painfully aware the rotation of the bowling order was out of sync, and time was rapidly running out as the wides kept coming.
Levin told their final pair to just make sure they survived the final over, rather than trying to score runs, and their 250-9 was immediately converted to 286-9 as Collegiate went six overs past their allotted time.
It meant Collegiate had to attack from the outset on the school ground with its long boundaries, and they were all chipped out for 167 in the 38th over.
Daemon Kennett (5-37) was the main recipient, backed by Curtis Maclachlan (3-37), as Collegiate were never going to climb back from 48-3 in the 16th over.
The biggest fight came from the middle order in Angus Dinwiddie (30) and Kelt (32), while Greatbatch (33) had a flurry in the tail.
At Paraparaumu Domain, the champions signalled they have got their steam back after raising 282-7 and then knocking the in-form Kapiti over for 136.
Scoreboard:
Tech 251 (Q Mailman 46, J Watkin 35, H Morrison 24, A Kumar 21, A Gill 20; S O'Leary 3-30, Z O'Keeffe 2-57) lost to Marist 253-8 (C Stewart 117no, M O'Leary 54, Z O'Keeffe 31; J Watkin 3-47, R Kinnerley 2-53) by two wickets.
United 322 (M Boswell 94, S Badger 63, G Hobbs 46, G Smith 37, M Pennefather 31; F Lane 2-35) bt Marton 89 (A Canderle 29no; R Verma 5-25, S Badger 3-19, J Pennefather 2-14) by 233 runs.
Levin 286-9 (D Sanson 74, B Tomo 39, N O'Brien 27, 36 penalty runs; H O'Leary 3-47, C Greatbatch 2-27, B Kelt 2-52).
Paraparaumu 282-7 (R Lorimer 83, R Subasinghe 56, B Gill 38, N Harvey 36, J Ross 30; Z Benton 3-53) bt Kapiti 136 (W Tharaka 59, J Miles 22, T Halbert 21; N Harvey 5-19, C Emmott 2-13, D McNamara 2-17) by 146 runs.